The global wildlife trade is doing more than threatening endangered species — it is quietly accelerating the spread of infectious diseases from animals to humans, according to a new Yale University study published in Science.

The research shows that the longer animals circulate through wildlife markets and trade networks, the more opportunities viruses, bacteria, and other pathogens have to jump into people, increasing the risk of future outbreaks of disease. 

For every 10 years an animal spends in the wildlife trade, it shares an average of one new pathogen with humans, the study found. The risk is even higher in the illegal wildlife trade and live animal markets, where animals from different regions and species are packed together under stressful, often unsanitary conditions. 

“Microbes move fast, but this is just staggering,” said Colin Carlson, assistant professor of epidemiology at the Yale School of Public Health and a co-author of the paper. “Wildlife trade has been affecting our health much faster, and for much longer, than we thought.” 

Outpatient early methadone dose titration – as recommended in Canadian and US clinical guidance for individuals using fentanyl – is associated with improved treatment retention and lower risk of opioid toxicity, according to new retrospective cohort study 

A Cedars-Sinai study published in Science reveals that the same neurons used to perceive objects once also reactivate when imagining them later.

EPFL researchers show that cholera bacteria can exchange protective genes, including antiviral immune systems, when they live in aquatic environments. The finding helps explain how these pathogens survive viral attacks and evolve in marine habitats.

A study conducted at the Department of Ecology and Evolution of the University of Lausanne quantifies the impact of wildlife trade on the exchange of germs and parasites between animals and humans. It was published on 9 April 2026 in the journal Science.

In this Editorial, Michael Lauer and Mark Barnes argue that creating more awareness of misconduct by individuals in the scientific enterprise could go a long way toward rebuilding the scientific commu­nity’s credibility. While some progress has been made in the way of encouraging universities and research institutions to share infor­mation about staff with potential future em­ployers, it is “likely too piecemeal to have a major impact,” say the authors. They point to the medical field’s National Practitioner Data Bank (NPDB) – established in 1990 and hosted by the Department of Health and Human Services – as a model for a better approach. State medical boards, health care entities, and certain other interested parties must report any adverse medical staff actions to the NPDB. Access to it is limited to health care entities so that infor­mation about professional problems is available only to prospective employers and state medical boards. “Surveys of NPDB us­ers indicate that the law is working as intended, helping institutions avoid potentially prob­lematic hires but not acting as an arbitrary or capricious blacklist,” say Lauer and Barnes. They advocate for a national scientist databank similar to the NPDB. “Discovering a previous behavioral problem [in the data bank] would not bar an institution from going ahead with the hire, but at least there would be transparency so that preventive steps could be taken by the new employer,” they say.

The global wildlife trade – especially in illegal and live-animal markets – is fueling the spread of diseases from animals to humans, according to a new study. The findings show that traded mammals are more than 40% more likely to harbor human-infecting pathogens, with species accumulating more shared pathogens the longer they remain in the trade. Close interactions between humans and wild animals create pathways for the spread of parasites and pathogens, sometimes triggering epidemics and pandemics. The global wildlife trade, which encompasses hunting, breeding, transport, retail, and pet ownership, poses particularly high risks of animal-to-human pathogen spillover. This trade has been linked to outbreaks ranging from HIV and Ebola to COVID-19 and mpox. While research has explored environmental and ecological factors that influence pathogen transmission, the dynamics of disease spread specifically within the wildlife trade and between humans and traded animals remain poorly understood.

 

Jérôme Gippet and colleagues analyzed 40 years of global wildlife trade data drawn from the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), the Law Enforcement Management Information System (LEMIS), and the Dataset of Seized Wildlife and their intended uses (DSW) datasets. They then linked this to the CLOVER database, which catalogs over 190,000 mammal-pathogen associations, to identify which species are known to share pathogens with humans. Gippet et al. found that among the 2,079 mammal species involved in global trade, 41% were found to share at least one pathogen with humans, compared with only 6.4% of nontraded species, and that traded mammals are 1.5 times more likely to host pathogens transmissible to humans. According to the authors, this suggests that cross-species transmission is an inherent feature of wildlife trade. Species in live-animal markets and, to a lesser extent, those involved in illegal trade, host more pathogens than those traded solely as products or legally. What’s more, the findings show that the duration a species spends in trade further amplifies risk. Gippet et al. found that each decade a species is traded corresponds to one additional pathogen shared with humans, on average.

Punishing freeloaders in public good games (PPGs) – experimental models used to analyze the social dilemma between individual self-interest and group cooperation – can boost cooperation, but whether punishment helps or harms the groups’ outcomes depends heavily on context, according to a study involving over 7,000 human participants. The findings reveal when, rather than whether, punishment works. Human societies routinely confront so-called “social dilemmas” – situations in which individual incentives clash with the collective good. These scenarios can arise in contexts ranging from public health to environmental policy. When they occur, cooperation – or prioritizing shared benefit over personal gain – is both essential and difficult to sustain. PPGs offer a simplified model for examining these dynamics. Although the group benefits most when everyone contributes fully, individuals can maximize their personal gain by contributing nothing. One widely studied solution to this problem is costly peer punishment, where individuals penalize those who fail to contribute. While this mechanism can discourage selfish behavior, it comes at a cost to both punisher and punished. Past studies have shown that, in some cases, the burden of punishment outweigh its benefits. However, despite this body of research, the conditions under which punishment best promotes cooperation remains unclear.

 

To better understand these dynamics, Mohammed Alsobay and colleagues conducted a large integrative experiment, systematically varying 14 features of PPGs (e.g. communication, group structure, incentives) across 360 conditions, analyzing more than 147,000 decisions from 7,100 participants. According to Alsobay et al., the experimental design allowed them to precisely identify when punishment helps or hinder shared outcomes, which factors matter most, and how they interact. The authors found that punishment consistently increased cooperation, but its effect on collective welfare varied dramatically – from a 43% improvement to a 44% reduction – depending on context. According to the study, communication was the most influential factor and was roughly three times more consequential than any other variable. Other important elements include how contributions are framed, the structure of contribution choices, the duration of the interaction, and the visibility of others’ outcomes. Notably, the findings show that these factors do not operate in isolation but interact in complex ways. For example, longer interactions only enhance the effectiveness of punishment when communication is possible. The authors also used the data to develop and train a predictive model that was able to outperform humans when predicting whether punishment would help or harm welfare in new experiments.